http://us2.php.net/manual/en/function.parse-str.php

And if you must use commas just str_replace it with &.

I was going to post about parse_str, but you already had done so. However, the posted function does have the ability to work with name-value pairs that have spaces around the deliminator, and parse_str doesn't seem to.

Please provide an example of input string and output array.

I would also rewrite your function, adding a second optional parameter - delimiter.